1. Field of the Invention
The present general inventive concept relates to a photographing apparatus and an image pickup device thereof, and more particularly, to a complementary metal oxide semiconductor (CMOS) type photographing apparatus which employs a rolling shutter method and an image pickup device thereof.
2. Description of the Related Art
An image pickup device is an element to generate an image in a mobile phone camera or a digital still camera (DSC). The image pickup device includes a charge coupled device (CCD) and a complementary metal oxide semiconductor (CMOS). The CCD is characterized in high quality, high cost, and high power consumption, and the CMOS is characterized in low quality, low cost, low power consumption, and multifunction.
However, with the development of semiconductor process and circuit technologies, a noise characteristic, which is a main disadvantage of the CMOS, has been improved, and recently, the CMOS is utilized in the machine vision field that requires high definition and high performance.
As a method for reading out an optical image from an object captured on an image pickup area of the image pickup device, a global shutter method and a rolling shutter method are suggested. In the global shutter method, all of pixels of the image pickup area read out an optical image at a same time. In the rolling shutter method, one or several pixels in the image pickup area read out an optical image in sequence.
The CMOS type image pickup device can employ both the global shutter method and the rolling shutter method. Since all of the pixels read out an optical image from an object at the same time in the global shutter method, a photographed image is not deformed even if the object moves.
Alternatively, in the CMOS type image pickup device employing the rolling shutter method, since one or several pixels read out an optical image in sequence, a photographed image is likely to be deformed if the object moves. Accordingly, if a moving object is photographed, a photographing apparatus employing the rolling shutter method has difficulty reproducing a normal image, which causes an inconvenience to users.
The users wish to obtain a high definition image when photographing an object. Accordingly, there has been a demand for lessening a degree of deformation of a photographed image for a moving object.